net/sunrpc/auth_gss/gss_krb5_crypto.c

   1 /*
   2  *  linux/net/sunrpc/gss_krb5_crypto.c
   3  *
   4  *  Copyright (c) 2000 The Regents of the University of Michigan.
   5  *  All rights reserved.
   6  *
   7  *  Andy Adamson   <andros@umich.edu>
   8  *  Bruce Fields   <bfields@umich.edu>
   9  */
  10
  11 /*
  12  * Copyright (C) 1998 by the FundsXpress, INC.
  13  *
  14  * All rights reserved.
  15  *
  16  * Export of this software from the United States of America may require
  17  * a specific license from the United States Government.  It is the
  18  * responsibility of any person or organization contemplating export to
  19  * obtain such a license before exporting.
  20  *
  21  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
  22  * distribute this software and its documentation for any purpose and
  23  * without fee is hereby granted, provided that the above copyright
  24  * notice appear in all copies and that both that copyright notice and
  25  * this permission notice appear in supporting documentation, and that
  26  * the name of FundsXpress. not be used in advertising or publicity pertaining
  27  * to distribution of the software without specific, written prior
  28  * permission.  FundsXpress makes no representations about the suitability of
  29  * this software for any purpose.  It is provided "as is" without express
  30  * or implied warranty.
  31  *
  32  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  33  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  34  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  35  */
  36
  37 #include <linux/err.h>
  38 #include <linux/types.h>
  39 #include <linux/mm.h>
  40 #include <linux/slab.h>
  41 #include <linux/scatterlist.h>
  42 #include <linux/crypto.h>
  43 #include <linux/highmem.h>
  44 #include <linux/pagemap.h>
  45 #include <linux/sunrpc/gss_krb5.h>
  46
  47 #ifdef RPC_DEBUG
  48 # define RPCDBG_FACILITY        RPCDBG_AUTH
  49 #endif
  50
  51 u32
  52 krb5_encrypt(
  53         struct crypto_blkcipher *tfm,
  54         void * iv,
  55         void * in,
  56         void * out,
  57         int length)
  58 {
  59         u32 ret = -EINVAL;
  60         struct scatterlist sg[1];
  61         u8 local_iv[16] = {0};
  62         struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
  63
  64         dprintk("RPC:      krb5_encrypt: input data:\n");
  65         print_hexl((u32 *)in, length, 0);
  66
  67         if (length % crypto_blkcipher_blocksize(tfm) != 0)
  68                 goto out;
  69
  70         if (crypto_blkcipher_ivsize(tfm) > 16) {
  71                 dprintk("RPC:      gss_k5encrypt: tfm iv size to large %d\n",
  72                          crypto_blkcipher_ivsize(tfm));
  73                 goto out;
  74         }
  75
  76         if (iv)
  77                 memcpy(local_iv, iv, crypto_blkcipher_ivsize(tfm));
  78
  79         memcpy(out, in, length);
  80         sg_set_buf(sg, out, length);
  81
  82         ret = crypto_blkcipher_encrypt_iv(&desc, sg, sg, length);
  83
  84         dprintk("RPC:      krb5_encrypt: output data:\n");
  85         print_hexl((u32 *)out, length, 0);
  86 out:
  87         dprintk("RPC:      krb5_encrypt returns %d\n",ret);
  88         return(ret);
  89 }
  90
  91 EXPORT_SYMBOL(krb5_encrypt);
  92
  93 u32
  94 krb5_decrypt(
  95      struct crypto_blkcipher *tfm,
  96      void * iv,
  97      void * in,
  98      void * out,
  99      int length)
 100 {
 101         u32 ret = -EINVAL;
 102         struct scatterlist sg[1];
 103         u8 local_iv[16] = {0};
 104         struct blkcipher_desc desc = { .tfm = tfm, .info = local_iv };
 105
 106         dprintk("RPC:      krb5_decrypt: input data:\n");
 107         print_hexl((u32 *)in, length, 0);
 108
 109         if (length % crypto_blkcipher_blocksize(tfm) != 0)
 110                 goto out;
 111
 112         if (crypto_blkcipher_ivsize(tfm) > 16) {
 113                 dprintk("RPC:      gss_k5decrypt: tfm iv size to large %d\n",
 114                         crypto_blkcipher_ivsize(tfm));
 115                 goto out;
 116         }
 117         if (iv)
 118                 memcpy(local_iv,iv, crypto_blkcipher_ivsize(tfm));
 119
 120         memcpy(out, in, length);
 121         sg_set_buf(sg, out, length);
 122
 123         ret = crypto_blkcipher_decrypt_iv(&desc, sg, sg, length);
 124
 125         dprintk("RPC:      krb5_decrypt: output_data:\n");
 126         print_hexl((u32 *)out, length, 0);
 127 out:
 128         dprintk("RPC:      gss_k5decrypt returns %d\n",ret);
 129         return(ret);
 130 }
 131
 132 EXPORT_SYMBOL(krb5_decrypt);
 133
 134 static int
 135 process_xdr_buf(struct xdr_buf *buf, int offset, int len,
 136                 int (*actor)(struct scatterlist *, void *), void *data)
 137 {
 138         int i, page_len, thislen, page_offset, ret = 0;
 139         struct scatterlist      sg[1];
 140
 141         if (offset >= buf->head[0].iov_len) {
 142                 offset -= buf->head[0].iov_len;
 143         } else {
 144                 thislen = buf->head[0].iov_len - offset;
 145                 if (thislen > len)
 146                         thislen = len;
 147                 sg_set_buf(sg, buf->head[0].iov_base + offset, thislen);
 148                 ret = actor(sg, data);
 149                 if (ret)
 150                         goto out;
 151                 offset = 0;
 152                 len -= thislen;
 153         }
 154         if (len == 0)
 155                 goto out;
 156
 157         if (offset >= buf->page_len) {
 158                 offset -= buf->page_len;
 159         } else {
 160                 page_len = buf->page_len - offset;
 161                 if (page_len > len)
 162                         page_len = len;
 163                 len -= page_len;
 164                 page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1);
 165                 i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT;
 166                 thislen = PAGE_CACHE_SIZE - page_offset;
 167                 do {
 168                         if (thislen > page_len)
 169                                 thislen = page_len;
 170                         sg->page = buf->pages[i];
 171                         sg->offset = page_offset;
 172                         sg->length = thislen;
 173                         ret = actor(sg, data);
 174                         if (ret)
 175                                 goto out;
 176                         page_len -= thislen;
 177                         i++;
 178                         page_offset = 0;
 179                         thislen = PAGE_CACHE_SIZE;
 180                 } while (page_len != 0);
 181                 offset = 0;
 182         }
 183         if (len == 0)
 184                 goto out;
 185
 186         if (offset < buf->tail[0].iov_len) {
 187                 thislen = buf->tail[0].iov_len - offset;
 188                 if (thislen > len)
 189                         thislen = len;
 190                 sg_set_buf(sg, buf->tail[0].iov_base + offset, thislen);
 191                 ret = actor(sg, data);
 192                 len -= thislen;
 193         }
 194         if (len != 0)
 195                 ret = -EINVAL;
 196 out:
 197         return ret;
 198 }
 199
 200 static int
 201 checksummer(struct scatterlist *sg, void *data)
 202 {
 203         struct hash_desc *desc = data;
 204
 205         return crypto_hash_update(desc, sg, sg->length);
 206 }
 207
 208 /* checksum the plaintext data and hdrlen bytes of the token header */
 209 s32
 210 make_checksum(s32 cksumtype, char *header, int hdrlen, struct xdr_buf *body,
 211                    int body_offset, struct xdr_netobj *cksum)
 212 {
 213         char                            *cksumname;
 214         struct hash_desc                desc; /* XXX add to ctx? */
 215         struct scatterlist              sg[1];
 216         int err;
 217
 218         switch (cksumtype) {
 219                 case CKSUMTYPE_RSA_MD5:
 220                         cksumname = "md5";
 221                         break;
 222                 default:
 223                         dprintk("RPC:      krb5_make_checksum:"
 224                                 " unsupported checksum %d", cksumtype);
 225                         return GSS_S_FAILURE;
 226         }
 227         desc.tfm = crypto_alloc_hash(cksumname, 0, CRYPTO_ALG_ASYNC);
 228         if (IS_ERR(desc.tfm))
 229                 return GSS_S_FAILURE;
 230         cksum->len = crypto_hash_digestsize(desc.tfm);
 231         desc.flags = CRYPTO_TFM_REQ_MAY_SLEEP;
 232
 233         err = crypto_hash_init(&desc);
 234         if (err)
 235                 goto out;
 236         sg_set_buf(sg, header, hdrlen);
 237         err = crypto_hash_update(&desc, sg, hdrlen);
 238         if (err)
 239                 goto out;
 240         err = process_xdr_buf(body, body_offset, body->len - body_offset,
 241                               checksummer, &desc);
 242         if (err)
 243                 goto out;
 244         err = crypto_hash_final(&desc, cksum->data);
 245
 246 out:
 247         crypto_free_hash(desc.tfm);
 248         return err ? GSS_S_FAILURE : 0;
 249 }
 250
 251 EXPORT_SYMBOL(make_checksum);
 252
 253 struct encryptor_desc {
 254         u8 iv[8]; /* XXX hard-coded blocksize */
 255         struct blkcipher_desc desc;
 256         int pos;
 257         struct xdr_buf *outbuf;
 258         struct page **pages;
 259         struct scatterlist infrags[4];
 260         struct scatterlist outfrags[4];
 261         int fragno;
 262         int fraglen;
 263 };
 264
 265 static int
 266 encryptor(struct scatterlist *sg, void *data)
 267 {
 268         struct encryptor_desc *desc = data;
 269         struct xdr_buf *outbuf = desc->outbuf;
 270         struct page *in_page;
 271         int thislen = desc->fraglen + sg->length;
 272         int fraglen, ret;
 273         int page_pos;
 274
 275         /* Worst case is 4 fragments: head, end of page 1, start
 276          * of page 2, tail.  Anything more is a bug. */
 277         BUG_ON(desc->fragno > 3);
 278         desc->infrags[desc->fragno] = *sg;
 279         desc->outfrags[desc->fragno] = *sg;
 280
 281         page_pos = desc->pos - outbuf->head[0].iov_len;
 282         if (page_pos >= 0 && page_pos < outbuf->page_len) {
 283                 /* pages are not in place: */
 284                 int i = (page_pos + outbuf->page_base) >> PAGE_CACHE_SHIFT;
 285                 in_page = desc->pages[i];
 286         } else {
 287                 in_page = sg->page;
 288         }
 289         desc->infrags[desc->fragno].page = in_page;
 290         desc->fragno++;
 291         desc->fraglen += sg->length;
 292         desc->pos += sg->length;
 293
 294         fraglen = thislen & 7; /* XXX hardcoded blocksize */
 295         thislen -= fraglen;
 296
 297         if (thislen == 0)
 298                 return 0;
 299
 300         ret = crypto_blkcipher_encrypt_iv(&desc->desc, desc->outfrags,
 301                                           desc->infrags, thislen);
 302         if (ret)
 303                 return ret;
 304         if (fraglen) {
 305                 desc->outfrags[0].page = sg->page;
 306                 desc->outfrags[0].offset = sg->offset + sg->length - fraglen;
 307                 desc->outfrags[0].length = fraglen;
 308                 desc->infrags[0] = desc->outfrags[0];
 309                 desc->infrags[0].page = in_page;
 310                 desc->fragno = 1;
 311                 desc->fraglen = fraglen;
 312         } else {
 313                 desc->fragno = 0;
 314                 desc->fraglen = 0;
 315         }
 316         return 0;
 317 }
 318
 319 int
 320 gss_encrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf,
 321                     int offset, struct page **pages)
 322 {
 323         int ret;
 324         struct encryptor_desc desc;
 325
 326         BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
 327
 328         memset(desc.iv, 0, sizeof(desc.iv));
 329         desc.desc.tfm = tfm;
 330         desc.desc.info = desc.iv;
 331         desc.desc.flags = 0;
 332         desc.pos = offset;
 333         desc.outbuf = buf;
 334         desc.pages = pages;
 335         desc.fragno = 0;
 336         desc.fraglen = 0;
 337
 338         ret = process_xdr_buf(buf, offset, buf->len - offset, encryptor, &desc);
 339         return ret;
 340 }
 341
 342 EXPORT_SYMBOL(gss_encrypt_xdr_buf);
 343
 344 struct decryptor_desc {
 345         u8 iv[8]; /* XXX hard-coded blocksize */
 346         struct blkcipher_desc desc;
 347         struct scatterlist frags[4];
 348         int fragno;
 349         int fraglen;
 350 };
 351
 352 static int
 353 decryptor(struct scatterlist *sg, void *data)
 354 {
 355         struct decryptor_desc *desc = data;
 356         int thislen = desc->fraglen + sg->length;
 357         int fraglen, ret;
 358
 359         /* Worst case is 4 fragments: head, end of page 1, start
 360          * of page 2, tail.  Anything more is a bug. */
 361         BUG_ON(desc->fragno > 3);
 362         desc->frags[desc->fragno] = *sg;
 363         desc->fragno++;
 364         desc->fraglen += sg->length;
 365
 366         fraglen = thislen & 7; /* XXX hardcoded blocksize */
 367         thislen -= fraglen;
 368
 369         if (thislen == 0)
 370                 return 0;
 371
 372         ret = crypto_blkcipher_decrypt_iv(&desc->desc, desc->frags,
 373                                           desc->frags, thislen);
 374         if (ret)
 375                 return ret;
 376         if (fraglen) {
 377                 desc->frags[0].page = sg->page;
 378                 desc->frags[0].offset = sg->offset + sg->length - fraglen;
 379                 desc->frags[0].length = fraglen;
 380                 desc->fragno = 1;
 381                 desc->fraglen = fraglen;
 382         } else {
 383                 desc->fragno = 0;
 384                 desc->fraglen = 0;
 385         }
 386         return 0;
 387 }
 388
 389 int
 390 gss_decrypt_xdr_buf(struct crypto_blkcipher *tfm, struct xdr_buf *buf,
 391                     int offset)
 392 {
 393         struct decryptor_desc desc;
 394
 395         /* XXXJBF: */
 396         BUG_ON((buf->len - offset) % crypto_blkcipher_blocksize(tfm) != 0);
 397
 398         memset(desc.iv, 0, sizeof(desc.iv));
 399         desc.desc.tfm = tfm;
 400         desc.desc.info = desc.iv;
 401         desc.desc.flags = 0;
 402         desc.fragno = 0;
 403         desc.fraglen = 0;
 404         return process_xdr_buf(buf, offset, buf->len - offset, decryptor, &desc);
 405 }
 406
 407 EXPORT_SYMBOL(gss_decrypt_xdr_buf);